


Unexpected, Though Not Unwanted

by SansyFresh



Series: Fresh's Babble Collection [23]
Category: Undertale (Video Game)
Genre: Fluff, M/M, Mating Cycles/In Heat, Papyrus is a Good Brother, Sans is anxious, skelepreg, slight angst
Language: English
Status: Completed
Published: 2017-05-23
Updated: 2017-05-24
Packaged: 2018-11-03 22:04:43
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 2,260
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10976253
Author URL: https://archiveofourown.org/users/SansyFresh/pseuds/SansyFresh
Summary: This wan't what was supposed to happen. But now that it has, Sans is just going to have to roll with it.





	1. Chapter 1

**Author's Note:**

> Just an idea I had from the sentence that popped in my head :
> 
> "I’m 283 years old, I raised your ungrateful ass when I was 102. I can’t fucking do this again."
> 
> Which, obviously means that this is one of my headcanons lol I've just never written anything with it before. And yes, it extends to all AUs. 
> 
> Enjoy!!!

Well this wasn’t how it was supposed to go. If Sans was certain of anything in this damn hell hole, it was that.

 

Going into heat was normal. Finding someone to help him out was also normal. What wasn’t fucking normal was the damn sight he was treated to now. The hem of his red sweater lifted to his sternum, empty sockets locked down onto his softly glowing ecto-belly, Sans could only stare in shock at the tiny soulling that floated without a care in his dark crimson magic. It was a good thing Boss wasn’t home yet to see just how fucking out of it he was right now, because he wasn’t sure he could form a coherent thought, let alone sentence.

 

It was just a one night stand. It wasn’t supposed to mean anything. But, for whatever reason, it did, and now Sans was saddled with the result. After a long moment of staring Sans finally sat back into the couch, the slight discomfort he had been feeling that prompted his investigation in the first place returning. What the hell was he going to do? 

 

Well, he could either sit here until Pap got home and worry himself into a panic attack, or he could take the time to get a good nap and ignore the problem. Seeing as how he was knocked up by the one monster he could trust, sleeping away his problems sounded like a damn good idea.

 

~.~

 

“Sans, I’m not entirely certain I understand.” Sans groaned at the blank look he was receiving from his little brother. Papyrus knew about the bird and the bees, it wasn’t that complicated.

 

“I went into heat, went and screwed Grillby, and now I’m knocked up. Does that explain it any better, Boss?” Sarcasm dripped from his tone, but rather than get angry like he normally did, Papyrus simply looked more confused.

 

“If you fucked Grillby, why did you get pregnant?” It was a fair question. Sans rubbed at his face for a moment, trying to decide how best to explain it. Papyrus waited patiently, though his eyelights kept drifting towards his brother’s middle.

 

“Usually which monster gets pregnant depends on which one has the most magic. Which was me.” Sans shrugged, leaning back in his chair. Of course that was just his luck. Papyrus seemed to digest the information for a moment, before accepting it as fact and moving on. He stood and went about preparing dinner, Sans only then becoming aware of the fact he was starving. This was already the worst.

 

“Well, congratulations then. I’m sure you’ll be a good parent.” The way Papyrus said it left no room for discussion, as though he was certain there was no way for Sans to be a bad parent. Sans huffed and laid his head on the table.

 

“I’m 283 years old, I raised your ungrateful ass when I was 102. I can’t fucking do this again.” His voice must had betrayed the rising panic he felt, because Papyrus paused once more, beside him in a moment to provide reassurance. His lil bro really was too cool.

 

“Brother, this is not something to panic about. I will be here for you, I’m sure once you tell Grillby that he will be here for you.” Papyrus paused, a small twinkle of mischief in his sockets. “I’ve seen the way he looks at you, brother. I’m sure he was waiting for you to go into heat for a while now.” Papyrus gave him a gentle pat on the shoulder, already conscientious of hurting the baby somehow. Sans gave him a glare for the comment, but relaxed marginally.

 

“I won’t be able to keep them safe, bro. Not here. I barely kept you from getting your skinny ass dusted, and that was almost two hundred years ago.” Sans sighed, resting his chin in his arms. He watched as Papyrus went through the steps of making his signature lasagna, a contemplative frown on his face.

 

“You won’t have to do it alone this time, brother. As First Lieutenant I can give you leave from your sentry position. No one will dare attack you when I am around, and if you insist on visiting your lover in that damn grease trap I’m sure he will protect you in your fragile state.”

 

Sans choked. “We’re not fucking lovers!” He glared heatedly, though the deep crimson blush that bloomed over his skull was telling. Papyrus simply smirked.

 

“You must be more than fuck-buddies if your first time together led to a child. But my point remains.” Papyrus nodded to himself decisively, considering the topic closed as he went on with his cooking. Sans watched passively, his brother’s words helping a little in staving off the panic he felt. His little brother was right about one thing; Grillby liked him a little more than he tended to let on, only proven by the fact that Sans still hadn’t been able to pay off his rather deplorable tab. But would he want to help out with the kid? Hell, would he even want Sans to  _ keep  _ it? 

 

The thought put a twist in his soul. If Grillby wanted him to abort it, then that would answer whether or not he would keep the bartender in his life. It was a weird sensation, how protective he already felt for the tiny soulling. There would be no talk of killing it.

 

“Thanks Pap.” Sans mumbled, sockets half lidded as he watched Papyrus set his plate before him, piled high with cheesy, saucy flat-noodles. His brother sat to his side, as they always did, with his own plate. He smiled, catching the double meaning in Sans’ words. 

 

“You’re welcome Sans. Now eat your damn lasagna before it gets cold, I won’t having you feed your child on a diet of mustard.” With that Papyrus began eating, leaving Sans to chuckle and start cutting his own bite. He paused, staring at his brother for a moment, before grinning.

 

“You’ll make a good uncle, Boss.” He smirked as the idea fully sunk into the other’s mind, leading to Papyrus laughing excitedly and talking about all the things they needed to do to get ready for his nibling. Sans just smiled and nodded as he fed both himself and his child with good, magic-fueled food.

  
Maybe this wouldn’t be a disaster after all.


	2. Flames and Kisses

**Notes for the Chapter:**

> And so it continues.
> 
> Lol here ya guys go, hope it satisfies lol
> 
> Enjoy!!

He hadn’t been this nervous in...well, there really was no way for him to know the exact time. It had been too long, apparently, because this was edging into him having a silent panic attack. But he had promised Paps he’d go talk to Grillby…Why the fuck had he made such a stupid promise? Damn pregnancy emotions.

 

Well, there was no running back to the house, Grillby had already seen him through the window, if the brief flare he saw was any indication. If he turned tail now he’d never be able to come back, and Grillby would be devastated. _He must really like guys with massive amounts of debt and shitty humor._ Sans chuckled to himself, shaking his head before finally entering the bar. What Grillby saw in him was something he’d probably never understand.

 

Everything went as it usually did as he passed by the tables full of the Dog Guard and the citizens of Snowdin. The dogs growled at him, though Dogaressa had a contemplative look on her face. Sans could only hope that meant they would leave him alone, rather than paint an even larger target on his back before it had to be. Everyone else simply glared at him, Grillby included, but that was more or less the flame’s resting expression.

 

Sans savored the fact that he could still get up on the bar stool with relative ease; he doubted he would retain that capability later on in term. Once he was settled, he turned his easy smirk on Grillby, who looked unamused. Well, that could be about anything, there was no way he had guess already.

 

“Where the fuck have you been?” Ah. It had been a while hadn’t it. Boss hadn’t wanted him to leave the house for at least a month or so to get past the first stages of sickness and volatile magic control. Not that he had great control over his magic in the first place, but he was glad he had stopped teleporting random places.

 

He still hadn’t lived down ending up under Paps bed. While the fucker was sleeping. That had been an awkward morning.

 

“I’ve been busy, firesprite. Had some shit to take care of.” Sans gave a shit-eating grin. “Why, you miss me?” Grillby flushed minutely at the pet name, only spoken loud enough for him to hear, but glared all the same.

 

“You still owe me a rather impressive amount of money, Sans. I intend to collect at some point.” The sentence was meant to be a threat, but the effect was lessened by the news Sans still needed to share. There came the familiar knot in his stomach. Sans sighed, rubbing at his face for a moment and ignoring the extremely subtle look of concern Grillby was giving him. “The regular?” Sans grimaced, shaking his head. This time the concern was obvious, though only to Sans.

 

“I just need to talk to ya. Not looking forward to it, but it’s important.” He frowned as Grillby seemed to close off, going back to cleaning a glass. “Grillby.” He waited until he had the other’s attention before he spoke again, his voice adamant. “It’s important.”

 

Grillby sighed, then went about throwing monsters out, whether they were ready to leave or not. Quite a few sent a glare in Sans’ direction as they left, like the fuckers could do anything. Soon it was just him and the bartender, Grillby looking apprehensive. Sans could guess what he was worried about.

 

He was right.

 

“Is it about what happened during your heat cycle? Because you came to me, I want you to know. We didn’t do anything either of us were uncomfortable with, I made sure of it.” Sans grinned to himself, shaking his head as he joined the other at a table, where they could speak face to face.

 

“Trust me, firesprite, you were a damn good lay. That was never an issue.” Sans chuckled as Grillby seemed to sigh in relief, the flame sitting back in his chair, a bit more relaxed. Which was good; Sans was grateful the other was sitting down for this. “It’s more what happened after that that we need to talk about.” Confusion was really the only thing he could read, which meant that he really was going to have to just come out and say it.

 

Great. Fantastic. Fucking wonderful.

 

“You got me pregnant, Grillby.” It was like ripping off a bandage, just saying it, forcing the words out of his fanged mouth. He stared at the chipped wood of the table, one hand clenched in his lap. He couldn’t imagine Grillby would want anything to do with the child, which was fine. “You don’t have to worry about anything, I can take care of it. Boss has already given me time off of my sentry position. Just thought you should probably know.”

 

The silence continued on and on, past the point of Sans being worried the other would attack him or something equally stupid. He finally got the courage to look up, only to find that Grillby had passed out and was steadily slipping out of his chair. “Holy shit, Grillbz!”

 

~.~

 

“He fainted? Really?” Sans was snickering, Grillby sitting at his side as Papyrus finished cleaning up after dinner. Grillby was hiding his face in his hands, blue flame sparking between his fingers every so often.

 

“Yep. Told him he was a dad and the bastard just up and passed out. About hit his head on the way to the floor if I hadn’t caught him.” Incoherent grumbles emitted from the flustered bartender, leading Sans to continue his guffawing.

 

Once he had gotten the firesprite awake once more, Grillby had expressed his desire to not only make Sans his partner, but to help him with the kid. Sans figured he shouldn’t have been surprised; really, he and Grillby had been unofficial partners for years already. The fact that he was so ready to be a father had surprised him, however. Not that he asked.

 

No need to jinx it.

 

Then, once Sans had determined it was time to head back home, Grillby had refused to let him go alone, already protective as hell. Not that Sans minded if he was being honest. The flame was a sturdy wall of protection, both for him and his kid. He couldn’t hope for any better, not with his brother being as supportive as he was as well.

 

Sans was startled out of his laughter by a quick, heated peck to his teeth, Grillby staring at him with a leer. Papyrus studiously ignored the sudden romantic tension in the room, something Sans was grateful for.

 

He might as well have hearts in his eyes, he loved this bastard so much. It was a love he hoped his kid could feel as well, to know that even if they were going to be born in the worst possible place, they had family who loved them.

 

And so he returned the kiss, prompting Pap to finally leave the room with a noise of disgust, leading to more laughter. This really was better than he thought it would be.

 

No need to jinx it.


End file.
